Helmet Safety Standards - SA2010 And What It Means To You

Almost two years ago, the Snell Foundation began working on a new standard for motorsports helmets. Known as SA2010, the standard has a number of significant changes from SA2005. Far and away the biggest change relates to how the helmets are tested for impact and subsequently passed/rejected by the foundation. That effectively means that the new SA2010 is incompatible with the established SA2005. Given that incompatibility, it's entirely possible that your SA2005-labeled helmet may not meet the new standard. Depending on the rules of your chosen series, sanction, or track you may have to buy a new helmet.

2/8With the new SA2010 standards from Snell now in place, custom helmet companies like Indocil Art find themselves busier than ever. Ryan Young

Going one step further, since SA2005 and SA2010 are not compatible, meeting SA2010 requirements will not automatically qualify a helmet to be produced and distributed with SA2005 labeling. Any SA2010 helmet distributed with SA2005 labeling must also have met requirements in SA2005 testing.

When the new standard was introduced, we here at Circle Track knew it would be important for our readers to understand the methodology behind the test and why now might just be the perfect time to upgrade that brain bucket of yours. Remember a helmet should be replaced immediately if damaged, and at least every five years based on wear and tear. Next to your belts, helmets are the most important piece of safety equipment in your racing program.

The Basics
Before we delve into the new standard itself let's have a brief review of how to select the proper helmet. Snell has come up with a nifty little way to help you find a good helmet. It's as easy as remembering the four S's: Size, Strap, Straight, and Snell.

Size: Try on several different helmets before you purchase one. The best way to gauge comfort level and fit is through comparison. The helmet should fit comfortably all the way around your head. Additional pads can be used to make it snug.

Strap: Pay attention to the chin strap. Make sure that the chin strap fits under your chin snugly and comfortably. The helmet should not shift on your head.

Straight: Know how a helmet should fit. A helmet is meant to be worn low on the forehead, just above your eyebrows. Your cheeks should also be pushed up slightly to ensure a snug fit. However, it should not hurt or be painful. Look into a mirror or have a friend help you determine the proper fit.

3/8It took less than 20 seconds for this M-rated helmet to become fully engulfed in flames. Could you get out of your race car that quickly?

Snell: Look for Snell certification, SA2010 or SAH2010. Snell Standards are the most stringent in the world, exceeding those set by the Consumer Products Safety Commission (CPSC), American Society of Testing Materials (ASTM), and the American National Standards Institute (ANSI).

The Big Three
Over the usable lifetime of a helmet, it will only really be needed for about 2 to 4 milliseconds, yet having the right equipment to protect your head is paramount to surviving those milliseconds. Therefore, it's important to know the differences between helmet ratings. In and around motorsports you'll often see three different alphanumeric designations for Snell ratings; SA, M, and K. The SA standard is designed for competitive auto racing, while the M standard is for motorcycling and other motorsports. The K standard accommodates helmets used in karting.

There are three major differences between them:

• The SA standard requires a flammability test while the M and K standards do not.
• The SA and K standards allow for a narrower visual field than M standard (Some SA- and K-certified helmets may not be street legal).
• The SA and K standards include a rollbar multi impact test while the M standard does not.

Without a doubt if you're climbing into any type of race car, you must have an SA-rated helmet. Refer back to Circle Track's Feb. '08 issue (page 56), when we set the M-rated helmet on fire, and you'll know why.

The New Standard
The most significant difference between SA2005 and SA2010 revolves around how Snell conducts the impact testing of the helmets. And one major criteria the Foundation adopted was to demand that less force be transmitted to the head during an impact, from 300 g's to 275 g's or less.

4/8Chart 1: Some of the testing changes contained in the new standard are a new head form designation "C" added between A and E and changes in drop mass relative to head form circumference.

However, there are also some straight forward changes which we'll tackle first. In the labeling department, all helmets must be marked with the largest and smallest appropriate head circumferences in centimeters. This is a departure from the sizing structure of S, M, L, and so on that some manufacturers typically use.

The second change involves the samples used for testing. Depending on the helmet's intended size range Snell may ask the manufacturer to provide up to eight samples for certification testing. This ensures more uniform results across the test sample.

Finally, there are provisional testing and separate "SAH2010" or "KH2010" certification labels for head-restraint-ready helmets, which we'll get into a little bit later. If a model is not head-restraint-ready, this provision won't apply, but the model may still be considered for SA2010 or K2010 certification.

With the simple changes out of the way, let's dive into the most important change.

Impact Test Differences
The differences between SA2010 and SA2005 all stem from a reevaluation of impact test head forms. SA2005 and previous standards required impact testing on head forms with an effective mass of 5.00 kg regardless of head form circumference. In other words, the previous standard assumed that everybody's head weighed 5 kg or about 11 pounds.

5/8Chart 2: This table shows the head forms considered appropriate to head size ranges in terms of centimeters of circumference. If a helmet's specified size range falls into one of the light gray cells, only a single head form is deemed appropriate and only six samples are required for testing. Otherwise, two or more head forms are indicated and the manufacturer must provide two additional samples for testing.

This reevaluation of head form mass is supported by a study conducted at the University of Washington by Dr. Randal Ching. Dr. Ching performed measurements on 15 cadaver heads and found a strong correlation between head mass and circumference. This correlation approximates a cubic mass versus circumference relationship and suggests that the ECE 22-05 (the current mandatory motorcycle helmet standard throughout Europe) mass specification would enable a more precise fit between the properties of Snell-certified helmets and the needs of their wearers across a broad range of different head sizes. Translation? The bigger your head is the more it weighs. Makes sense, doesn't it?

In order to accommodate the new specification Snell had to change both the test procedure and the test criteria. In SA2005, if a helmet met requirements on a larger head form, the same helmet would obtain comparable results on smaller head forms. Not so for SA2010, each test criteria (head form mass, g-level test, and more) are correlated to each other. As you can see in Chart 1 a new head form designation "C" has been added between A and E.

In this same chart you can see how the drop mass (head form mass) changes in regards to the head form circumference. The certification test criteria for the medium and smaller sizes, head forms A through J, are all set to 275 g. The value comes directly from ECE 22-05. But this 275 g value, combined with the head form mass changes, would allow larger helmets to transmit more shock than allowed by SA2005. So, for the M and O head forms, the largest sizes, the peak G levels have been reduced even further to assure that SA2010 never allows any more shock than the Foundation allowed previously. The bottom line is that SA2010 helmets will absorb more impact.

6/8Snell’s test apparatus for SAH2010 helmet certification. Three separate tests are performed on the anchor points; symmetrical frontal impact tests (pictured above) at two different loads, and an offset test. In order for a helmet to achieve certification, it must pass all three tests.

The certification velocities replace the impact energy requirements of previous Snell standards. The energy requirements in SA2005 effectively demanded impact velocities of approximately 7.75 m/sec followed by 6.62 m/sec. However, the different impact masses must necessarily impose progressively greater levels of stress within the helmet structure as head form mass increases. Therefore, smaller sized helmets will be able to satisfy the test criteria in SA2010 at higher impact velocity levels than larger helmets. Since, like previous Snell standards, SA2010 will call out double impacts, the first certification impact will be at 7.75 m/sec regardless of head form size. The second impacts for the A, C, and E head forms are set to 7.09 m/sec but are set progressively lower for the J through O head forms to allow for the limits of current materials and design technology.

The RST (Retention Strength Testing) now calls for the helmet sample to be supported on its lower edge. This is intended to eliminate and test failure due to liner compression. This test's criteria are uniformly higher than the certification criteria in order to ensure that, during standards enforcement, measurement uncertainty will not reasonably cause a good helmet to fail.

7/8Illustration 1: Here you can see a close up of how Snell’s lifting eye, which is used in the dual clip or symmetrical test, is fitted to the HNR anchor point.

However, RST testing calls for the same impact velocities as certification and which are also subject to measurement uncertainties. If velocity uncertainty should cause a helmet to fail in RST, the matter will be set tight in a second round of enforcement testing.

When a helmet fails in RST, three more samples are tested to confirm that failure. The same RST criteria apply but these samples are tested at deviation level velocities which are uniformly lower than certification test velocities. If all three samples meet the test requirements, the previous RST failure is thrown out. But if any of the samples fail, it's back to the drawing board for the manufacturer.

Helmet Sizing Concerns
Helmets must meet requirements over their entire range of head sizes. In previous Snell standards, if a helmet met impact requirements on the largest appropriate head form, it would also meet them reliably on smaller test head forms. But, for SA2010, helmets must be tested on the largest and smallest appropriate head forms if there is to be any confidence that helmets will meet requirements reliably throughout their intended size ranges. Snell has a procedure for determining the largest head form a helmet will fit but, unfortunately, it knows of no good way to determine which might be the smallest head form. Instead, SA2010 will require manufacturers to declare the intended size range of each helmet submitted for certification, as you can see outlined in Chart 2.

Head-and-Neck Restraints
One of our favorite topics here at CT is the head-and-neck restraint. As part of the new Snell standards the Foundation has added a standard specifically for HNRs in the form of an addendum. Helmets that meet all the requirements for SA2010 and which also meet the addendum's requirements will be eligible for SAH2010 certification labels indicating FHR (frontal head restraint) capability.

8/8Illustration 2: For the single clip, or offset test, the lifting eye is attached differently.

In order for a helmet with provisions for what many call "HANS clips" to be tested and (presumably) certified, it must pass a fairly stringent set of limitations before testing, including all necessary hardware is already fixed in the helmet shell with M6 female threads accessible through holes in the shell for the attachment of helmet tether assemblies. There will be at least four turns of thread securing the tether attachment within the shell fixed hardware. A minimum footing area between the tether attachment and the exterior surface of the helmet shell with minimum intrusion of the hardware into the helmet interior is required. The limitations also require that the inner surface of the helmet's shock liner be no closer than 20 mm to the innermost surface of the shell fixed hardware.

The head-and-neck restraint helmets are then subjected to three separate tests; symmetrical frontal impact tests at two different loads, and an offset test. In order for a helmet to achieve certification, it must pass all three tests. The procedures, which are shown in the photo on the following page and Illustrations 1 and 2, test the strength and durability of the clips, anchors, and tethers.

The Bottom Line
The new SA2010 specs functionally require helmet manufacturers to make more actual sizes of helmets, which results in overall better fitting helmets with a better size-to-weight ratio in many cases. Although the differences in testing criteria make SA2005 and SA2010 incompatible, Snell representatives say that the SA2005-certified helmets still offer a high level of protection. What the 2010 standards offer is a more realistic interpretation of human biological factors in the test methodologies. The bottom line is that there will be more and better head and head-and-neck protection for racers. By the time you read this, all of the major helmet manufacturers will have their SA2010 helmets on the shelves ready to ship to you. With the new season here, now may be the perfect time to upgrade from that old SA2005 helmet.